Edward L. Lee

Efficacy of open-label bismuth subsalicylate for the treatment of microscopic colitis

BACKGROUND & AIMS The pathogenesis of the microscopic colitis syndrome is unknown but may involve bacteria, an intestinal luminal antigen, and/or autoimmunity. It was hypothesized that bismuth subsalicylate would resolve both diarrhea and colonic inflammation in microscopic colitis because it possesses antidiarrheal, antibacterial, and anti-inflammatory properties. METHODS Thirteen patients with microscopic colitis (7 with subepithelial collagen deposition and 6 without) were treated with eight chewable 262-mg bismuth subsalicylate tablets per day for 8 weeks. Patients recorded the frequency of bowel movements daily. Forty-eight-hour stool collections and flexible sigmoidoscopy with 24 biopsies were performed before and after treatment in each patient. RESULTS Twelve patients completed the trial. Eleven patients had a resolution of diarrhea and a reduction in fecal weight. The average time to respond was 2 weeks. In 9 patients, colitis resolved. When present before treatment, subepithelial collagen thickening disappeared. Those completing the trial experienced no side effects. Posttreatment follow-up for 7-28 months shows that 9 patients remain well having undergone no further treatment, 2 are well but required retreatment, and 1 has continued diarrhea. CONCLUSIONS Bismuth subsalicylate treatment for 8 weeks is safe and well tolerated. This regimen appears to be efficacious for the treatment of microscopic colitis and is worthy of further study in a controlled trial.

Bone marrow progenitor cells contribute to esophageal regeneration and metaplasia in a rat model of Barrett's esophagus

Barretts esophagus develops when refluxed gastric juice injures the esophageal squamous lining and the injury heals through a metaplastic process in which intestinal-type columnar cells replace squamous ones. The progenitor cell that gives rise to Barretts metaplasia is not known, nor is it known why the condition is predisposed to malignancy. We studied the contribution of bone marrow stem cells to the development of Barretts esophagus in an animal model. Twenty female rats were given a lethal dose of irradiation followed by tail vein injection of bone marrow cells from male rats. Ten days later, the female rats were randomly assigned to undergo either esophagojejunostomy, a procedure that causes reflux esophagitis with intestinal metaplasia, or a sham operation. The rats were killed at 8 weeks and serial sections of the snap-frozen esophagi were cut and mounted on slides. The first and last sections were used for histological evaluation and the intervening sections were immunostained for cytokeratin to identify epithelial cells and analyzed for Y chromosome by fluorescence in situ hybridization (FISH). Histological evaluation of the esophagi from rats that had esophagojejunostomy revealed ulcerative esophagitis and multiple areas of intestinal metaplasia. FISH analyses showed that some of the squamous epithelial cells and some of the columnar epithelial cells lining the glands of the intestinal metaplasia were positive for Y chromosome. These observations suggest that multi-potential progenitor cells of bone marrow origin contribute to esophageal regeneration and metaplasia in this rat model of Barretts esophagus.

COLCHICINE TOXICITY: DISTINCT MORPHOLOGIC FINDINGS IN GASTROINTESTINAL BIOPSIES

Colchicine is an alkaloid with antimitotic ability used to treat a variety of medical conditions. Colchicine toxicity can result in multiorgan failure and death. The histopathologic features of colchicine toxicity in gastrointestinal biopsies have not been reported. Twenty-one gastrointestinal mucosal biopsies obtained from nine patients receiving oral colchicine therapy were studied. Immunohistochemical staining for Ki67 proliferation antigen was performed, and medical records of each patient were reviewed. All patients had a history of gout. Four patients with chronic renal failure also had clinical evidence of colchicine toxicity, and the other five patients did not. Distinct morphologic changes, seen as metaphase mitoses, epithelial pseudostratification, and loss of polarity, were seen in biopsy material from 4 of 4 (100%) patients with clinical colchicine toxicity. Three of these four cases (75%) also contained abundant crypt apoptotic bodies. These morphologic features were best seen in the biopsies from duodenum and gastric antrum, with relative sparing of the gastric body in the upper gastrointestinal tract. Ki67 staining demonstrated an expansion of the proliferating region in three available cases with clinical colchicine toxicity. These distinctive morphologic features were not seen in the five patients without clinical colchicine toxicity. These results indicate that colchicine toxicity can produce diagnostic morphologic features in gastrointestinal mucosal biopsies. Recognition of these features is important because colchicine toxicity can be fatal if undiagnosed clinically.

Distinct BRAF (V600E) and KRAS Mutations in High Microsatellite Instability Sporadic Colorectal Cancer in African Americans

Purpose: Colorectal cancer develops through genetic, epigenetic, and environmental events that result in uncontrolled cell proliferation. Colorectal cancer incidence and mortality is higher in African Americans (AA) than in the general population. Here, we carried out a molecular analysis of sporadic colorectal cancer tumors from AAs to investigate possible explanations for the observed disparities. Experimental Design: A total of 222 AA colorectal cancer tumors were analyzed for microsatellite instability (MSI) for protein expression of two DNA mismatch repair genes, MLH1 and MSH2, by immunohistochemistry; for the methylation silencing of MLH1, p16, APC, and APC2 promoters by methylation-specific PCR; and for point mutations in two oncogenes, KRAS and BRAF, by sequencing. Results: In our sample, 19.8% of the AAs colorectal cancer tumors were MSI high (MSI-H) and did not associate with any of the clinicopathologic features, except tumor differentiation. Higher levels of inactive DNA mismatch repair proteins MLH1 (41%) and MSH2 (33%) were found by immunohistochemistry. Methylation-specific PCR analysis revealed a high level of methylation for MLH1 (66%), APC (53%), and APC2 (90%), but not for p16 (26%). BRAF mutations were only within the MSI-H tumors, whereas most (64%) of KRAS mutations were found within the non–MSI-H group. Conclusions:MLH1, MSH2, and BRAF alterations are significantly associated with MSI-H phenotype, unlike APC, APC2 and KRAS alterations. The prominent role of DNA mismatch repair gene suppression in MSI-H and a distinctive role of BRAF and KRAS mutations with respect to MSI status are supported by this study.

Factors Influencing Gastroduodenal Mucosal Prostaglandin Concentrations: Roles of Smoking and Aging

OBJECTIVE To evaluate behavioral, demographic, clinical, and histologic variables that independently influence gastroduodenal mucosal prostaglandin concentrations. DESIGN Prospective study. SETTING A clinical research laboratory located in a Department of Veterans Affairs hospital. PATIENTS Fifty-two healthy adults who had no history of peptic ulcer disease and who were not receiving nonsteroidal anti-inflammatory drugs. MEASUREMENTS Mucosal biopsy specimens were obtained endoscopically from the stomach (body and antrum) and the duodenum (bulb and postbulbar area). Mucosal extracts from each of these four regions were assessed by radioimmunoassay to determine prostaglandin E2 and prostaglandin F2 alpha concentrations. Specimens were also examined histologically for inflammation and the presence of Helicobacter pylori. A multivariate linear regression model was used to determine which behavioral, demographic, and histologic variables significantly and independently influenced gastroduodenal mucosal prostaglandin concentrations. RESULTS Smoking and older age were independently associated with lower prostaglandin concentrations in all four mucosal regions (P = 0.0001 to P = 0.05). Compared with results in young nonsmokers, mucosal prostaglandin concentrations were reduced by 70% to 80% in older smokers. Gender, alcohol use, endoscopic appearance, dyspeptic symptoms, mucosal inflammation, and the presence of H. pylori had no consistent effect on prostaglandin content. CONCLUSION Smoking and older age are associated with significantly reduced gastric and duodenal prostaglandin concentrations. These observations may help explain the predisposition to ulcer disease in smokers and older persons.

Relationship between Campylobacter pylori and gastritis in healthy humans after administration of placebo or indomethacin

Endoscopic and microscopic appearances of antral and fundic mucosa were correlated with the presence or absence of Campylobacter pylori--and with plasma immunoglobulin G antibodies to that organism--in 23 healthy volunteers, 12 of whom had received indomethacin and 11 of whom had received no medication. Antral C. pylori, found in 9 of 23 biopsy specimens (3 of 11 controls, 6 of 12 indomethacin-treated patients; not significantly different), correlated strongly with histologic evidence of active superficial antral gastritis (p less than 0.005), but not with the endoscopic appearance of the antrum. In contrast to the antrum, fundic C. pylori, found in 14 of 23 biopsy specimens (61%), were frequently associated with histologically and endoscopically normal fundic mucosa. Campylobacter pylori-associated active antral gastritis occurred only in subjects whose fundus harbored this organism. Plasma immunoglobulin G antibody titers to C. pylori were highest in subjects with Campylobacter-associated antral gastritis and lowest in subjects without gastric Campylobacter. These studies suggest that healthy humans may harbor C. pylori in their proximal stomach without apparent ill effects. In some of these individuals, the organism also involves the antrum and is associated with active gastritis.

Effects of Helicobacter pylori gastritis on gastric secretion in healthy human beings.

Helicobacter pylori gastritis is common, but effects on gastric secretion are not well understood. We measured basal and pentagastrin-stimulated gastric acidity, pepsin activity, and fluid output, as well as serum gastrin concentrations and H. pylori antibody levels, before and after treatment of H. pylori gastritis in 28 men and women. Subjects were studied before and 1 and 3 mo after a course of bismuth, metronidazole, and tetracycline. Elimination of H. pylori gastritis, accomplished in 14 subjects, increased basal and pentagastrin-stimulated gastric acidity (by 15 meq/l) and basal acid output significantly (by 2.1 meq/h 1 mo after therapy). Elimination of H. pylori had an opposite effect on pepsin secretion, significantly decreasing pepsin output by 30%. Elimination of H. pylori significantly reduced nonparietal fluid output by 35%, without affecting fluid output from parietal cells. Serum gastrin and H. pylori antibody levels declined significantly after elimination of H. pylori. None of these changes was observed in 14 subjects whose H. pylori gastritis was resistant to antimicrobial therapy. In summary, eradication of H. pylori infection increases gastric acidity by reducing nonparietal gastric secretion from peptic and other cells.

Influence of H. pylori infection on meal-stimulated gastric acid secretion and gastroesophageal acid reflux

Gastric acid secretion, gastrin release, gastric emptying, and gastroesophageal acid reflux were measured in asymptomatic individuals before and after elimination of Helicobacter pylorigastritis. After basal gastric acid secretion and serum gastrin concentrations were measured, meal-stimulated gastric acid secretion and gastrin release were assessed during in vivo intragastric titration to pH 3. Experiments were repeated 4 wk after treatment with lansoprazole, amoxicillin, and clarithromycin. Esophageal pH was also monitored for 24 h before and after therapy. Basal gastric acidity increased ∼20 mmol/l in subjects whose infection was eradicated ( P < 0.05) but not in those with persistent infection. Basal and meal-stimulated gastric acid secretion did not change after H. pylorieradication, despite a 41% reduction in meal-stimulated gastrin release ( P < 0.05). Gastroesophageal acid reflux increased two- to threefold after successful treatment ( P < 0.05) but did not change in subjects with persistent infection. Thus elimination of H. pylori gastritis increases gastric acidity, probably by reducing nonparietal alkaline secretion, and this may facilitate gastroesophageal acid reflux.Gastric acid secretion, gastrin release, gastric emptying, and gastroesophageal acid reflux were measured in asymptomatic individuals before and after elimination of Helicobacter pylori gastritis. After basal gastric acid secretion and serum gastrin concentrations were measured, meal-stimulated gastric acid secretion and gastrin release were assessed during in vivo intragastric titration to pH 3. Experiments were repeated 4 wk after treatment with lansoprazole, amoxicillin, and clarithromycin. Esophageal pH was also monitored for 24 h before and after therapy. Basal gastric acidity increased approximately 20 mmol/l in subjects whose infection was eradicated (P < 0.05) but not in those with persistent infection. Basal and meal-stimulated gastric acid secretion did not change after H. pylori eradication, despite a 41% reduction in meal-stimulated gastrin release (P < 0.05). Gastroesophageal acid reflux increased two- to threefold after successful treatment (P < 0. 05) but did not change in subjects with persistent infection. Thus elimination of H. pylori gastritis increases gastric acidity, probably by reducing nonparietal alkaline secretion, and this may facilitate gastroesophageal acid reflux.

Synovial sarcoma of the stomach: a clinicopathologic, immunohistochemical, and molecular genetic study of 10 cases.

Only a few synovial sarcomas arising in the gastrointestinal tract have been reported, most of them are from the esophagus. We report clinical, histopathologic, and immunohistochemical features of 10 gastric synovial sarcomas. These tumors occurred in 4 males and 6 females with mean and median age of 52 years (range, 29 to 68 y). None of the patients had evidence of synovial sarcoma elsewhere. The tumor sizes ranged from 0.8 to 15 cm (mean, 3 cm). Two tumors were large transmural masses of 8 and 15 cm, and 8 were 0.8 to 6 cm, ulcerated cuplike or plaquelike or oval lesions predominantly involving the luminal side. Histologically, 9 tumors were monophasic one also having a poorly differentiated round cell component, and one was biphasic. Microscopic calcifications were present in 2 tumors. At least focal keratin (AE1/AE3 cocktail, keratin 7) and/or epithelial membrane antigen-positivity were detected in all tumors, and there was no CD34 or KIT-immunoreactivity. SYT-SSX fusion transcripts were demonstrated in 7 cases studied by a polymerase chain reaction-based fusion transcript assay. Five patients had a partial gastrectomy, and 5 underwent wedge or segmental resections. Two patients had received chemotherapy after surgery, but none had postoperative radiation. Four patients with plaquelike or cuplike tumors ≤3 cm were alive and well 1, 2, 2, and 18.5 years after surgery. Two patients died of tumor 25 and 29 months after surgery. One of them had a large 8-cm tumor, and another had a 2-cm tumor with a poorly differentiated component. Two patients were alive with recurrences 6 and 48 months after diagnosis. Synovial sarcoma rarely occurs as a gastric primary tumor. It has a variable prognosis depending on tumor size and differentiation, and should be considered in the differential diagnosis of KIT-negative gastric spindle cell neoplasms.

Differences in ERK activation in squamous mucosa in patients who have gastroesophageal reflux disease with and without Barrett's esophagus.

OBJECTIVES:In some patients with gastroesophageal reflux disease (GERD), the reflux-damaged esophageal squamous epithelium heals through the process of intestinal metaplasia (resulting in Barretts esophagus) rather than through the regeneration of more squamous cells. We hypothesized that squamous epithelium in Barretts esophagus might have abnormalities in activation of the extracellular-regulated kinases 1 and 2 (ERK1/2) signaling pathway that may facilitate esophageal repair through metaplasia in response to acid-induced injury.METHODS:Endoscopic biopsies were taken from distal esophageal squamous mucosa in patients who had GERD with and without Barretts esophagus and in controls, before and after esophageal perfusion with 0.1 N HCl acid. Basal ERK1/2 phosphorylation, acid-induced ERK1/2 activity and phosphorylation, and localization of phosphorylated ERK1/2 were determined using immunoblotting, Western blotting, and immunohistochemistry.RESULTS:Compared to patients with Barretts esophagus, patients with GERD exhibited significantly lower baseline levels of phosphorylated ERK1/2 expression (35 ± 4% vs 90 ± 21% control, P = 0.01) Acid exposure significantly increased ERK1/2 activity (346.6 ± 51.90 to 446.8 ± 62.44 RIU, P = 0.02) and phosphorylation (3.55 ± 1.26 to 4.49 ± 1.25 [ratio phospho/total ERK], P = 0.01) in the squamous mucosa of GERD patients, but not in those with Barretts esophagus or in controls.CONCLUSIONS:Between patients with Barretts esophagus and patients with uncomplicated GERD, there are significant differences in baseline levels and in acid-induced activation of ERK1/2 in esophageal squamous epithelium. To our knowledge, this is the first description of a molecular, phenotypic feature that distinguishes the esophageal squamous mucosa of GERD patients with and without Barretts esophagus.